Shaft seal



A. D. AMES March 5, 1940.

SHAFT SEAL Filed July '25, 1938 'INVENTOR. AEETHUIZ. D. Apes ATTORNEY.5.

Patented Mar. 5, 1940 UNITED STATES PATENT OFFICE SHAFT SEAL Arthur D.Ames, Lake Bracken, 111., assignor to Outboard, Marine & ManufacturingCompany, Waukegan, 111., a corporation of Delaware Application July 25,1938, Serial No. 221,107

.5 Claims.

This invention relates to improvements in shaft seals.

It is the object of the present invention to provide a novel andimproved shaft seal employing U gaseous or vapor pressure for theexpansion of inner and outer walls each provided with a bellows, thebellows of the inner wall and the I bellows of the outer wall being inradially overlapped staggered relation for economy and space.

1| Other objects will appearfrom the following disclosure. The drawingshows an axial section of a seal embodying this invention, with theinternal mechanism illustrated partially in side elevation and partiallyin section.

The shaft 3 is provided with a bearing in the housing member 4, which,by way of illustration,

may be taken to be the crank case of a compressor. Within housing 4 is aseal chamber 5 capped by a closure 6, having a bearing for the reducedportion I of the shaft. In accordance with conventional practice, theshaft is encircled adjacent shoulder 8 by a ring 9, over which seats thesocketed terminal member 10 of the seal. The opposite terminal member llof the seal is clamped between the closure 6 and the co-actin surface 12of housing 4.

In accordance with the preferred practice of the invention, the terminalmembers III and II are a connected by inner and outer bellows, andthe-gas or vaporwhich furnishes the pressure for the expansion of theseal is confined between suchbellows. The outer bellows 15 has all ofits convolutions l6 adjacent its left hand end and the I inner bellows11 has all of its convolutions l8 adjacent its right hand en'd. Asleeve-like extension 19 of the inner bellows projects through theconvoluted portion l6 of the outer bellows into engagement with theinner terminal ring 10 of the All seal, and, similarly, a sleeve-likeextension 20 of the outer bellows projects past the convoluted portionl8 of the'inner bellows into connection with the terminal ring ll of theseal.

The solder at 22 closes an opening in the sleeve, I portion 20 of theouter bellows through which the material for producing gas or vaporpressure for I the expansion of the bellows was introduced.

It is obviously immaterial what substance is employed to create therequisite pressure. It is likewise immaterial how much pressure isneeded.

Air, carbon dioxide, or any other gas ormixture of gases which willremain wholly or partly in' gaseous state at the temperatures at whichthe device operates may be used. It is likewise possil ble to introducesome liquids, or even solids, such,

for example, as liquid ammonia or frozen carbon dioxide, which, in theirvaporization or sublimation, will give ofi the gas or vapor to createthe desired degree of pressure.

Since the sealing device as illustrated has vari- .1

ous convolutions it will expand and contract freely in an axialdirection but will not yield appreciably in a radial direction. Thusall, or substantially all, of.the gas pressure applied within thebellows will be exerted in a direction to ex- 1 pand the seal, therebyseparating the terminal rings 10 and J I. Since the ring H is fixed inthe constructions shown, the expansion will take place in a direction tourge ring 10 to a tight seat upon .the annulus 9 and to maintain theannulus 9 ll tightly seated upon the shoulder 8 of shaft 3.

In actual tests the uniformity of pressure achieved in this method andthe possibility of controlling the pressure with greater accuracy thanit is possible to achieve in the production manufacture of springs, andalso the possibility of producing increases of pressure corresponding totemperature increases to which the device may be subject, all representadvantages of the present device as compared with the more conventionala spring actuated seal. I claim:

1. In a seal, the combination with terminal members, of inner and outerwall elements in connection therewith, said elements having staggered sobellows portions, and each having a sleeve portion radially overlappingthe bellows portion of the other. i

2. In a seal, an inner bellows member having a sleeve portion and aconvoluted bellows portion, an outer bellows member having'a sleeveportion radially overlapping the convoluted bellows portion of the firstmember and a convoluted bellows portion radially overlapping the sleeveportion of the first member, and means connecting the over- 0 lappingends of the respective members.

3. In a seal, the combination of a wall element of annular formcomprising relatively extensible and non-extensible portions, aconcentric annular wall element having a non-extensible" portionradially overlapping the extensible portion of the first wall element,and'an extensible portion radially overlapping thenon-extensible-portion of the first wall element, and means hermeticallyconnecting the ends ofthe respective wall elements 0 to constitute aclosed chamber therebetween.

4. In a seal, the combination with a first wall element comprising aconvoluted axially extensible portion and an adjacent tubular portion,of a second wall element comprising a tubular portion radiallyoverlapping the convoluted portion of the eter for the remainder of itslength, and the outer first element and axially extensible meansradially 'of said elements comprising a tubular portion of overlappingthe tubular portion of the first elerelatively large diametersurroundingthe bellows .ment, and means hermetically connecting the ofthe inner element and a bellows of relatively ends of the first andsecond elements to constitute small internal diameter surrounding thetubular- 6 a closed chamber. portion of the inner element, the internalradius- 5. In a seal, the combination with terminal of the bellows oftheouter-element being less than members of inner and outer aigiallyexpansible the external radius of the bellows of the inner elementshermetically connected to the respective element, whereby to provide forthe free eirpam members, the inner of said elements comprising a sionand contraction "of both elements with 10 tube of relatively smalldiameter for a portion of economy of space. Y its length and a bellowsof larger over-all diam: ARTHUR D. AMES.

